In chains especially of chained vehicles, ordinarily the links of the chain are interconnected via pivot hinges. In this connection this pivot hinge comprises a pin and a sleeve which is pushed with a swivelling capacity over the pin, with the links of the chain being pressed on the ends of the pin and the sleeve. The rotary bearing surfaces between the pin and the sleeve are lubricated by an oil chamber in the pin, the oil space between the pin and sleeve being sealed by two seal elements which comprises sealing lips which press against the front surfaces of the sleeve.
For example, DE 27 26 033 A1 discloses a chain pin arrangement with a seal, the chain pin arrangement comprising a chain pin with a part of a first chain link attached to the chain pin and a sleeve which can be moved back and forth relative to the pin and which surrounds one part of the chain pin, with a part of a second chain link attached to the sleeve. Furthermore the chain pin arrangement comprises a hollow made in the first chain link for holding the seal which is provided with its sealing lip for adjoining the front side of the sleeve, and a spacer ring which surrounds the chain pin, which extends in the axial direction between the front surface of the hollow and the front surface of the sleeve and its outer peripheral surface together with the front surface of the sleeve and the hollow forms a cavity for holding the seal. In this connection, the seal which has been inserted into the cavity comprises a main sealing ring of comparatively stiff, but elastic first elastomer material and an auxiliary seal element of a second elastic elastomer material which is much less stiff than the first material.
U.S. Pat. No. 4,607,854 discloses a seal arrangement for a chain pivot hinge in which there are a first ring of flexible elastomer material having a sleeve-like part and a flange-like part with a sealing lip, and a second sleeve which surrounds the first touching ring of elastic material for sealing the space between the pin and the sleeve surrounding the pin. Here the first ring comprises a cylindrical, metallic stiffening ring which is embedded completely in the sleeve-like part of the first ring.
The object of the invention is to devise a seal arrangement for sealing between the first part of the chain and a second part of the chain which can be at least pivoted relative to the first, and which has especially a long service life.
A seal arrangement for sealing between the first part of the chain and a second part of the chain which can be at least pivoted relative to the first contains the following features:                a sealing ring with an annular sealing lip for sealing the lubricant space between the parts which can be pivoted against one another,        an elastic ring for securely adjoining one of the parts and for applying pressure to the sealing ring and        a support ring located between the sealing ring and the elastic ring.        
The invention is based on the finding that for a conventional seal arrangement in which the elastic ring interacts directly with the sealing ring, the elastic ring when installed is deformed as intended such that it produces forces both in the axial and also radial direction, the radially acting forces after a certain time causing the sealing ring to be pressed by creep effects onto the cylindrical jacket-like opposing surface on the pin or spacer ring, so that the seal arrangement becomes immovable and can no longer equalize the axial tolerances; this ultimately causes leaks. Another contributing effect is the deformation of the sealing ring which forms upon axial movements of the pin or spacer ring as a result of the radially acting forces in conjunction with the friction of the sealing ring on the pin or spacer ring. The invention avoids the aforementioned adverse effects by inserting between the sealing ring and elastic ring a support ring with which the high radial forces are captured.
Because the support ring is simply placed between the sealing ring and the elastic ring during installation, the entire seal arrangement can be easily and thus economically produced. The seal arrangement achieves a much longer service life compared to comparable conventional seal arrangements at production costs which are roughly the same or even lower.
In one advantageous embodiment the support ring, the elastic ring, and the sealing ring are made matched to one another such that the elastic ring together with the sealing ring seals the support ring to the outside. This advantageously prevents penetration of moisture from the outside to the support ring so that the support ring especially when made as a metal ring is protected from corrosion.
In one advantageous configuration the elastic ring is made to form an annular sealing lip which upon proper deformation of the elastic ring when viewed from the outside is designed to adjoin one of the parts of the chain in front of the sealing lip of the sealing ring. This advantageously prevents penetration of dirt from the outside in the direction of the sealing lip of the sealing ring.
Other advantages, features and details of the invention will become apparent from the embodiment of the invention described below using the FIGURE.